Benign, borderline, and malignant ovarian epithelial neoplasms will be examined by molecular and interphase cytogenetic techniques to determine whether ovarian carcinoma develops from progressive cancerization of benign tumors or arises de novo. Alterations in chromosome number, loss of heterozygosity, oncogene amplification and mutation, deletion of tumor suppressor genes, and microsatellite instability will be assessed. These will also be examined in benign-appearing, borderline, and malignant elements within heterogeneous carcinomas, and used to compare pure versus heterogeneous, and serous versus mucinous, tumors. The presence and pattern of nonrandom aberrations should provide insight into the process of tumorigenesis. Cumulative genetic changes would suggest a multistep progression from benign to malignant, while the presence of very different genetic abnormalities would suggest independent origins.